The bobbing of the head that crowds do at a show when they don't know what else to do with themselves; approval of the show, or complete confusion and puzzlement of how their bodies should move, react, and connect.
OMG! I wanted to dance so bad, but with all the Hipster Head Bobbing people, I couldn't, I might just overwhelm them with my slight variety of moves that involve other parts of my body but my head!